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EHV May Remain Viable In Water For Three Weeks

A new study has shown that some equine herpes viruses (EHV) can remain viable in untreated water for over three weeks, becoming a source of infection for equids, reports Vet Times.

In many parts of the world, water sources are shared by horses, other equids and other species. If a horse that is actively shedding the EHV-1 virus visits the water and sheds the virus, the virus can remain there long after the animal has left.

The study challenges the long-held belief that the herpesvirus is unstable outside the host; it was believed that they are spread by direct aerosol transmission. However, animals like rhinos and polar bears have contracted EHV though they had no direct contact with horses or their relatives.

Conducted by researchers from the Leibniz Institute for Zoo and Wildlife Research and the Institut für Virologie of the Freie Universität Berlin, the results were reported in Science Daily. The team tested this assumption by spiking the water with EHV under various conditions over three weeks. They then examined it to see if the viral DNA could be retrieved and how infectious the virus was after having been in the water.

It was shown that the EHV-1 virus remains stable and infectious for up to three weeks. Water temperature and pH played the biggest role in whether or not the virus stayed alive. The addition of soil, which would mimic a natural body of water, actually seemed to “pull” the virus out of the water and into the soil, where it stabilized. This result suggests that EHV-1 can persist for an extended amount of time without infecting other animals. This also shows why some animals can be infected from these bodies of water long after the animal that shed the virus has left.